Cyperus diandrusTorr.

umbrella flatsedge

WFO wfo-0000371593 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Cyperus diandrus, photographed by Henry "Nick" Robertson
fig. a Henry "Nick" Robertson, CC BY-SA 4.0 / 2021-09-03 / obs. 155051331
Cyperus diandrus, photographed by Henry "Nick" Robertson
fig. b Henry "Nick" Robertson, CC BY-SA 4.0 / obs. 151484736
Cyperus diandrus, photographed by Quinten Wiegersma
fig. c Quinten Wiegersma, CC BY 4.0 / obs. 150687579
Cyperus diandrus, photographed by Quinten Wiegersma
fig. d Quinten Wiegersma, CC BY 4.0 / obs. 93204846
Cyperus diandrus, photographed by Owen Strickland
fig. e Owen Strickland, CC BY 4.0 / obs. 88261173
Cyperus diandrus, photographed by Étienne Léveillé-Bourret
fig. f Étienne Léveillé-Bourret, CC BY 4.0 / obs. 67430179
Cyperus diandrus, photographed by Zihao Wang
fig. g Zihao Wang, CC BY 4.0 / obs. 156943342
Cyperus diandrus, photographed by er-birds
fig. h er-birds, CC BY 4.0 / obs. 151905183

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 27 botanical countries

Regions where Cyperus diandrus is native: Alabama, Connecticut, Delaware, Illinois, Indiana, Iowa, Kansas, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Brunswick, New Hampshire, New Jersey, New York, Nova Scotia, Ontario, Pennsylvania, Québec, Rhode I., Tennessee, Vermont, Virginia, Wisconsin AlabamaConnecticutIllinoisIndianaIowaKansasMaineMarylandMassachusettsMichiganMinnesotaMissouriNebraskaNew BrunswickNew HampshireNew JerseyNew YorkNova ScotiaOntarioPennsylvaniaQuébecTennesseeVermontVirginiaWisconsin DelawareRhode I.
Native distribution of Cyperus diandrus, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows. Regions too small to draw at this scale are marked with a dot.
RegionTDWG codeContinent
Alabama ALA NORTHERN AMERICA
Connecticut CNT
Delaware DEL
Illinois ILL
Indiana INI
Iowa IOW
Kansas KAN
Maine MAI
Maryland MRY
Massachusetts MAS
Michigan MIC
Minnesota MIN
Missouri MSO
Nebraska NEB
New Brunswick NBR
New Hampshire NWH
New Jersey NWJ
New York NWY
Nova Scotia NSC
Ontario ONT
Pennsylvania PEN
Québec QUE
Rhode I. RHO
Tennessee TEN
Vermont VER
Virginia VRG
Wisconsin WIS

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Also published as 5 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Cyperus diandrus f. elongatus (Britton) Fernald
  • Cyperus diandrus var. elongatus Britton
  • Cyperus diandrus var. pauciflorus Alph.Wood
  • Pycreus diandrus (Torr.) C.B.Clarke
  • Torreya maritima Raf.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.